vect: more oversized bitmask fixups

These patches fix up a failure in testcase vect/tsvc/vect-tsvc-s278.c when
configured to use V32 instead of V64 (I plan to do this for RDNA devices).

The problem was that a "not" operation on the mask inadvertently enabled
inactive lanes 31-63 and corrupted the output.  The fix is to adjust the mask
when calling internal functions (in this case COND_MINUS), when doing masked
loads and stores, and when doing conditional jumps (some cases were already
handled).

gcc/ChangeLog:

	* dojump.cc (do_compare_rtx_and_jump): Clear excess bits in vector
	bitmasks.
	(do_compare_and_jump): Remove now-redundant similar code.
	* internal-fn.cc (expand_fn_using_insn): Clear excess bits in vector
	bitmasks.
	(add_mask_and_len_args): Likewise.